The social effects of evolutionary thought have been considerable. As the scientific explanation of life's diversity has developed, it has often displaced alternative, sometimes very widely held, explanations. Because the theory of evolution includes an explanation of humanity's origins, it has had a profound impact on human societies. Some have vigorously denied acceptance of the scientific explanation due to its perceived religious implications (e.g. its implied rejection of the special creation of humans presumably described in the Bible). This has led to a vigorous conflict between creation and evolution in public education, primarily in the United States.

The theory of evolution by natural selection has also been adopted as a foundation for various ethical and social systems, such as social Darwinism, an idea that preceded the publication of The Origin of Species, popular in the 19th century, which holds that "the survival of the fittest" (a phrase coined in 1851 by Herbert Spencer, 8 years before Darwin published his theory of evolution) explains and justifies differences in wealth and success among societies and people. A similar interpretation was one created by Darwin's cousin, Francis Galton, known as eugenics, which claimed that human civilization was subverting natural selection by allowing the less bright and less healthy to survive and out-breed the more smart and more healthy.

Later advocates of this theory suggested radical and often coercive social measures in an attempt to "correct" this imbalance. Thomas Huxley spent much time demonstrating through a series of thought experiments that it would not only be immoral, but impossible.[1]Stephen Jay Gould and others have argued that social Darwinism is based on misconceptions of evolutionary theory, and many ethicists regard it as a case of the is-ought problem. After the atrocities of the Holocaust became linked with eugenics, it greatly fell out of favor with public and scientific opinion, though it was never universally accepted by either, and at no point in Nazi literature is Charles Darwin or the scientific theory of evolution mentioned.[2][better source needed]

In his book The End of Faith, Sam Harris argues that Nazism was largely a continuation of Christian anti-Semitism. Jim Walker compiled a list of 129 quotes from Mein Kampf in which Hitler described himself as a Christian, or mentioned God, Jesus or a biblical passage.[3] Some[who?] argue that six million of the people killed during the Holocaust were killed because of their religion (Judaism) not their race, "strength," or any reason with an obvious link to the mechanism of Darwinian evolution. Hitler often used Christian beliefs like, "Jews killed Jesus," to justify his anti-Semitism.[4]

The notion that humans share ancestors with other animals has also affected how some people view the relationship between humans and other species. Many proponents of animal rights hold that if animals and humans are of the same nature, then rights cannot be distinct to humans.

Charles Darwin, in fact, considered "sympathy" to be one of the most important moral virtues — and that it was, indeed, a product of natural selection and a trait beneficial to social animals (including humans). Darwin further argued that the most "sympathetic" societies would consequently be the most "successful." He also stated that our sympathy should be extended to "all sentient beings":

As man advances in civilization, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all the members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races. If, indeed, such men are separated from him by great differences in appearance or habits, experience unfortunately shows us how long it is, before we look at them as our fellow-creatures. ... This virtue, one of the noblest with which man is endowed, seems to arise incidentally from our sympathies becoming more tender and more widely diffused, until they are extended to all sentient beings. As soon as this virtue is honored and practiced by some few men, it spreads through instruction and example to the young, and eventually becomes incorporated in public opinion.

Thomas Huxley, Darwin's Bulldog, spent much of his book Evolution and Ethics debunking Social Darwinism, piece by piece. The following is a summary of his arguments in the Prolegomena, the most detailed and comprehensive of the two sections devoted to it. It should be noted that Huxley is here attempting to disprove the science behind Social Darwinism; as such, the moral arguments only come in later in the essay.

Consider a garden. Without constant upkeep, it would return to the state of nature, even the very walls surrounding it crumbling in sufficient time, but by constant diligence of the gardener, may be maintained in a state of art. This "state of art" is not permanent: It is instead the replacement of natural selection by artificial selection through the human energy expended in maintaining it.

This artificial selection is, however, part of natural selection: It is the action upon a set of species by the human species by way of the human species expending energy through evolved intelligence on its choice of selection. It is thus no less natural than, for example, a predator expending energy through evolved instinct on preferentially hunting a certain prey species. The presence of humans may change the dynamic, but in a perfectly natural way. Hence, it is part of the cosmic process, that is natural laws, even though the "histological process" may remove many aspects of the "struggle for existence" that is a key part of the natural laws that apply to biology, from its preferred plant species by substituting human work for work done by the species itself.

Not only is the state of nature hostile to the state of art of the garden; but the principle of the horticultural process, by which the latter is created and maintained, is antithetic to that of the cosmic process. The characteristic feature of the latter is the intense and unceasing competition of the struggle for existence. The characteristic of the former is the elimination of that struggle, by the removal of the conditions which give rise to it. The tendency of the cosmic process is to bring about the adjustment of the forms of plant life to the current conditions; the tendency of the horticultural process is the adjustment of the conditions to the needs of the forms of plant life which the gardener desires to raise.

Nature uses unrestricted breeding to let hundreds compete for the natural resources that would only support one, and uses frost and drought to kill off the weak and unlucky, requiring not just strength, but "flexibility and good fortune." However, a gardener restricts multiplication, gives each plant sufficient space and nourishment, protects from frost and drought—and, in every other way, attempts to modify the conditions to benefit the forms that most nearly approach the result he desires. However, though the gardener's actions may have circumvented natural selection, he can still improve the species, should he find them wanting, through selective breeding. The struggle for existence is not actually required for improvement: only heritability, variation, and some form of selective pressure.

Can we then apply this to humans? Let's see how far we can take the analogy with respect to colonization:

Suppose a shipload of English colonists sent to form a settlement, in such a country as Tasmania was in the middle of the last century. On landing, they find themselves in the midst of a state of nature, widely different from that left behind them in everything but the most general physical conditions. The common plants, the common birds and quadrupeds, are as totally distinct as the men from anything to be seen on the side of the globe from which they come. The colonists proceed to put an end to this state of things over as large an area as they desire to occupy. They clear away the native vegetation, extirpate or drive out the animal population, so far as may be necessary, and take measures to defend themselves from the re-immigration of either. In their place, they introduce English grain and fruit trees; English dogs, sheep, cattle, horses; and English men; in fact, they set up a new Flora and Fauna and a new variety of mankind, within the old state of nature. Their farms and pastures represent a garden on a great scale, and themselves the gardeners who have to keep it up, in watchful antagonism to the old regime. Considered as a whole, the colony is a composite unit introduced into the old state of nature; and, thenceforward, a competitor in the struggle for existence, to conquer or be vanquished.

Under the conditions supposed, there is no doubt of the result, if the work of the colonists be carried out energetically and with intelligent combination of all their forces. On the other hand, if they are slothful, stupid, and careless; or if they waste their energies in contests with one another, the chances are that the old state of nature will have the best of it. The native savage will destroy the immigrant civilized man; of the English animals and plants some will be extirpated by their indigenous rivals, others will pass into the feral state and themselves become components of the state of nature. In a few decades, all other traces of the settlement will have vanished.

However, as yet we lack an organized gardener. Let us imagine an idealized one: an administrative authority of intelligence and foresight as much greater than men as men are to their livestock. The unwanted native species - men, animals, or plants - are all weeded out and destroyed. Those to replace them are chosen with a view to his ideal of the colony, just as a gardener tries to create through his selection his ideal garden. And, finally, to ensure that no struggle for existence between the colonists interferes with the struggle against nature, he provides them with sufficient food, housing, and so on. "With every step of this progress in civilization, the colonists would become more and more independent of the state of nature; more and more, their lives would be conditioned by a state of art. In order to attain his ends, the administrator would have to avail himself of the courage, industry, and co-operative intelligence of the settlers; and it is plain that the interest of the community would be best served by increasing the proportion of persons who possess such qualities, and diminishing that of persons devoid of them. In other words, by selection directed towards an ideal."

However, though this might create a paradise where every aspect of nature works to support its colonists, problems arise: "as soon as the colonists began to multiply, the administrator would have to face the tendency to the reintroduction of the cosmic struggle into his artificial fabric, in consequence of the competition, not merely for the commodities, but for the means of existence. When the colony reached the limit of possible expansion, the surplus population must be disposed of somehow; or the fierce struggle for existence must recommence and destroy that peace, which is the fundamental condition of the maintenance of the state of art against the state of nature.

If the administrator is guided purely by scientific considerations, he would work to restrict the population by removing "the hopelessly diseased, the infirm aged, the weak or deformed in body or in mind, and the excess of infants born," just as a "gardener pulls up defective and superfluous plants, or the breeder
destroys undesirable cattle. Only the strong and the healthy, carefully matched, with a view to the progeny best adapted to the purposes of the administrator, would be permitted to perpetuate their kind."

And so we have reached Social Darwinism. However, we do not have an idealized administrator:

Of the more thoroughgoing of the multitudinous attempts to apply the principles of cosmic evolution, or what are supposed to be such, to social and political problems, which have appeared of late years, a considerable proportion appear to me to be based upon the notion that human society is competent to furnish, from its own resources, an administrator of the kind I have imagined. The pigeons, in short, are to be their own Sir John Sebright. A despotic government, whether individual or collective, is to be endowed with the preternatural intelligence, and with what, I am afraid, many will consider the preternatural ruthlessness, required for the purpose of carrying out the principle of improvement by selection, with the somewhat drastic thoroughness upon which the success of the method depends. Experience certainly does not justify us in limiting the ruthlessness of individual "saviors of society"; and, on the well-known grounds of the aphorism which denies both body and soul to corporations, it seems probable (indeed the belief is not without support in history) that a collective despotism, a mob got to believe in its own divine right by demagogic missionaries, would be capable of more thorough work in this direction than any single tyrant, puffed up with the same illusion, has ever achieved. But intelligence is another affair. The fact that "saviors of society" take to that trade is evidence enough that they have none to spare. And such as they possess is generally sold to the capitalists of physical force on whose resources they depend. However, I doubt whether even the keenest judge of character, if he had before him a hundred boys and girls under fourteen, could pick out, with the least chance of success, those who should be kept, as certain to be serviceable members of the polity, and those who should be chloroformed, as equally sure to be stupid, idle, or vicious. The "points" of a good or of a bad citizen are really far harder to discern than those of a puppy or a short-horn calf; many do not show themselves before the practical difficulties of life stimulate manhood to full exertion. And by that time the mischief is done. The evil stock, if it be one, has had time to multiply, and selection is nullified.

However, humans are not cattle, nor flowers: the organization of human society is kept together by

...bonds of such a singular character, that the attempt to perfect society after his fashion would run serious risk of loosening them. They do not even correspond to social insects such as bees: With bees, "The members of the society are each organically predestined to the performance of one particular class of functions only. If they were endowed with desires, each could desire to perform none but those offices for which its organization specially fits it; and which, in view of the good of the whole, it is proper it should do. Among mankind, on the contrary, there is no such predestination to a sharply defined place in the social organism. However much men may differ in the quality of their intellects, the intensity of their passions, and the delicacy of their sensations, it cannot be said that one is fitted by his organization to be an agricultural laborer and nothing else, and another to be a landowner and nothing else. Moreover, with all their enormous differences in natural endowment, men agree in one thing, and that is their innate desire to enjoy the pleasures and to escape the pains of life; and, in short, to do nothing but that which it pleases them to do, without the least reference to the welfare of the society into which they are born, checked only by sympathy, familial and social bonds, and fear of the judgment of ones fellow man. "Every forward step of social progress brings men into closer relations with their fellows, and increases the importance of the pleasures and pains derived from sympathy.

In short, he describes a creation of morality.

Since morality is what keeps the desire for selfishness in check, it is necessary to the propagation of society, with one requirement: the punishment of wrongdoers being necessary for the continuation of society, self-restraint must not be taken so far that wrongdoers may act unrestrained: Without the protection of society against them, "The followers of the "golden rule" may indulge in hopes of heaven, but they must reckon with the certainty that other people will be masters of the earth."[5]

Huxley sums up this section of his argument against Social Darwinism:

I have further shown cause for the belief that direct selection, after the fashion of the horticulturist and the breeder, neither has played, nor can play, any important part in the evolution of society; apart from other reasons, because I do not see how such selection could be practiced without a serious weakening, it may be the destruction, of the bonds which hold society together. It strikes me that men who are accustomed to contemplate the active or passive extirpation of the weak, the unfortunate, and the superfluous; who justify that conduct on the ground that it has the sanction of the cosmic process, and is the only way of ensuring the progress of the race; who, if they are consistent, must rank medicine among the black arts and count the physician a mischievous preserver of the unfit; on whose matrimonial undertakings the principles of the stud have the chief influence; whose whole lives, therefore, are an education in the noble art of suppressing natural affection and sympathy, are not likely to have any large stock of these commodities left. But, without them, there is no conscience, nor any restraint on the conduct of men, except the calculation of self-interest, the balancing of certain present gratifications against doubtful future pains; and experience tells us how much that is worth. Every day, we see firm believers in the hell of the theologians commit acts by which, as they believe when cool, they risk eternal punishment; while they hold back from those which are opposed to the sympathies of their associates.

Huxley finishes with a series of short, further evidences against Social Darwinism, including:

Historical evidences against: Consider the vast changes of society between the Tudor and the Victorian eras; however, human nature, as evidenced by their writing, remains the same. "In my belief, the innate qualities, physical, intellectual, and moral, of our nation have remained substantially the same for the last four or five centuries. If the struggle for existence has affected us to any serious extent (and I doubt it) it has been, indirectly, through our military and industrial wars with other nations."

Whether some qualities are virtues or vices depends on circumstance: "The benevolence and open-handed generosity which adorn a rich man, may make a pauper of a poor one; the energy and courage to which the successful soldier owes his rise, the cool and daring subtlety to which the great financier owes his fortune, may very easily, under unfavorable conditions, lead their possessors to the gallows, or to the hulks. Moreover, it is fairly probable that the children of a "failure" will receive from their other parent just that little modification of character which makes all the difference. I sometimes wonder whether people, who talk so freely about extirpating the unfit, ever dispassionately consider their own history. Surely, one must be very "fit," indeed, not to know of an occasion, or perhaps two, in one's life, when it would have been only too easy to qualify for a place among the "unfit.""

Before Darwin's argument and presentation of the evidence for evolution, Western religions generally discounted or condemned any claims that diversity of life is the result of an evolutionary process, as did most scientists in the English scientific establishment. However, evolution was accepted by some religious groups such as the Unitarian church and the liberal Anglican theologians who went on to publish Essays and Reviews. as well as by many scientists in France and Scotland and some in England, notably Robert Edmund Grant. Literal or authoritative interpretations of Scripture hold that a supreme being directly created humans and other animals as separate Created kinds, which to some means species. This view is commonly referred to as creationism. From the 1920s to the present in the US, there has been a strong religious backlash to the teaching of evolution theory, particularly by conservative evangelicals. They have expressed concerns about the effects of the teaching of evolution on society and their faith (see Creation-evolution controversy).

In response to the wide scientific acceptance of the theory of evolution, many religions have formally or informally synthesized the scientific and religious viewpoints. Several important 20th century scientists (Fisher, Dobzhansky) whose work confirmed Darwin's theory, were also Christians who saw no incompatibility between their experimental and theoretical confirmations of evolution and their faith. Some religions have adopted a theistic evolution viewpoint, where God provides a divine spark that ignited the process of evolution and (or), where God has guided evolution in one way or another.

The Roman Catholic Church, beginning in 1950 with Pope Pius XII's encyclical Humani Generis, took up a neutral position with regard to evolution. "The Church does not forbid that...research and discussions, on the part of men experienced in both fields, take place with regard to the doctrine of evolution, in as far as it inquires into the origin of the human body as coming from pre-existent and living matter."[6]

In an October 22, 1996, address to the Pontifical Academy of Science, Pope John Paul II updated the Church's position, recognizing that Evolution is "more than a hypothesis" - "In his encyclical Humani Generis, my predecessor Pius XII has already affirmed that there is no conflict between evolution and the doctrine of the faith regarding man and his vocation... Today, more than a half-century after the appearance of that encyclical, some new findings lead us toward the recognition of evolution as more than an hypothesis. In fact it is remarkable that this theory has had progressively greater influence on the spirit of researchers, following a series of discoveries in different scholarly disciplines."[7]

Classical figures have not discussed the subject as it has only come up in the 19th century. Contemporaries have come up with several distinct stances. One stance is that adaptation, or evolution on a micro scale, is accepted within a species, but cross-species evolution, that is evolution from one species into another species, is not as the human beginning is considered to be miraculous. However, this traditional thought would not conflict with the view that human-like beings could have been created around the same time as human beings, which, in this view, would explain the fossil records that look human but are not. Another stance is that since evolution is the simplest explanation it is the most reasonable to accept under the condition that it is not random but occurs only with the permission of God every step of the way. One particular argument that supports the idea that evolution is possible is the one stating that in that the stages of human development in evolution are akin to the distinct stages of development acknowledged in the Koran.[citation needed] The final stance completely rejects cross-species evolution across all organisms, but approves of adaptation (micro evolution).

Many important political figures on the left have never publicized their views on biology, and so their opinions of evolutionary theory are unknown. To some extent, Marxists are the exception. Karl Marx, Friedrich Engels and Vladimir Lenin supported Darwin's evolutionary theory. Marx even sent Darwin a copy of his book Das Kapital, though Darwin never wrote back to him. Karl Marx's work was based on a material view of the world that showed natural causes and effects for all aspects of human society and economy. He recognized that Darwin's work provided a similar material explanation for all of nature, thus supporting Marx's worldview.

In 1861 Karl Marx wrote to his friend Ferdinand Lassalle, "Darwin’s work is most important and suits my purpose in that it provides a basis in natural science for the historical class struggle. ... Despite all shortcomings, it is here that, for the first time, 'teleology' in natural science is not only dealt a mortal blow but its rational meaning is empirically explained."[8]

Most later Marxists agreed with this view, but some – particularly those in the early Soviet Union – believed that evolutionary theory conflicted with their economic and social ideals. As a result, they came to support Lamarckism instead – the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring. This led to the practice of Lysenkoism, which caused agricultural problems.

On the contemporary moderate left, some authors such as Peter Singer (in his book, A Darwinian Left) support Darwinism but reach different political and economic lessons than more conservative observers. Richard Dawkins' book, The Selfish Gene, has a chapter, "Nice guys finish first," that attempts to explain the role of altruism and cooperation in evolution and how social animals not only cannot survive without such traits, but how evolution will create them. Dawkins explains that when an animal sacrifices itself or uses its resources for the survival of other members of the same species, its genes, present on the other animals, survive. For example, if a mother dies to save three of its pups, one and a half copies (on average) of its genes will survive, because there is a 50% chance of a particular gene being present in its offspring. Dawkins also made a documentary of the same name.[9] According to the documentary, Dawkins added that chapter as a way of overcoming modern day misinterpretations of the concept of survival of the fittest.
Left-wing transhumanists see technology as a means to overcome inequalities that stem from biology. New left feminist Shulamith Firestone saw technological control over reproduction as essential for gender equality.[citation needed] More recently the Laboria Cuboniks collective has articulated an antinaturalist politics that seeks to overcome essentialist categories through technological empowerment.[10][clarification needed]

Social Darwinism is further linked with nationalism and imperialism.[15] During the age of New Imperialism, the concepts of evolution justified the exploitation of "lesser breeds without the law" by "superior races."[15] To elitists, strong nations were composed of white people who were successful at expanding their empires, and as such, these strong nations would survive in the struggle for dominance.[15] With this attitude, Europeans, except for Christian missionaries, seldom adopted the customs and languages of local people under their empires.[15]Christian missionaries, on the other hand, were the very first individuals to meet new peoples and develop writing systems for local inhabitants' languages that lacked one.[15] Being critics of Darwinism, they ardently opposed slavery and provided an education and religious instruction to the new peoples they interacted with since they felt that this was their duty as Christians.[15]

^Huxley credits Hartley (Observations on Man (1749), vol. ii p. 281.) for not only having "...laid the foundations but built up much of the superstructure of a true theory of the Evolution of the intellectual and moral faculties and for having realized that the creation of civilization will in itself create ethics, if not in an evolutionary context." as well as Adam Smith

^Darwin strongly disagreed with attempts by Herbert Spencer and others to extrapolate evolutionary ideas to all possible subjects; see Midgley, M (2004). The Myths we Live By. Routledge. p. 62. ISBN978-0-415-34077-9.

^ abcdefPerry, Marvin; Chase, Myrna; Jacob, Margaret; Jacob, James; Daly, Jonathan W.; Von Laue, Theodore H. (2014). Western Civilization: Ideas, Politics, and Society. Volume II: Since 1600 (11th ed.). Boston, MA: Cengage Learning. pp. 634–635. ISBN978-1-305-09142-9. LCCN2014943347. OCLC898154349. Retrieved 2016-02-01. The most extreme ideological expression of nationalism and imperialism was Social Darwinism. In the popular mind, the concepts of evolution justified the exploitation by the 'superior races' of 'lesser breeds without the law.' This language of race and conflict, of superior and inferior people, had wide currency in the Western nations. Social Darwinists vigorously advocated empires, saying that strong nations—by definition, those that were successful at expanding industry and empire—would survive and others would not. To these elitists, all white peoples were more fit than nonwhites to prevail in the struggle for dominance. Even among Europeans, some nations were deemed more fit than others for the competition. Usually, Social Darwinists thought their own nation the best, an attitude that sparked their competitive enthusiasm. ...In the nineteenth century, in contrast to the seventeenth and eighteenth centuries, Europeans, except for missionaries, rarely adopted the customs or learned the languages of local people. They had little sense that other cultures and other peoples deserved respect. Many Westerners believed that it was their Christian duty to set an example and to educate others. Missionaries were the first to meet and learn about many peoples and the first to develop writing for those without a written language. Christian missionaries were ardently opposed to slavery....